This invention is directed to expansion joints and, more particularly, to pipe joints of the expansion type having provision for the expansion and contraction caused by changes in temperature of the external environment or by a transmitted fluid while continuously sealing the connection.
Commercial pipe expansion joints presently in use assume many varied forms, such, for example, as disclosed in the U.S. Pat. No. 3,416,819. In this patent, two telescoping pipe members are joined by a sleeve of flexible material which folds upon itself for permitting the elongation and contraction of the pipe members in accordance with temperature changes of the fluid flowing therethrough.
Use of flexible boots for providing a fluid-tight seal between telescoping parts is disclosed in U.S. Pat. No. 3,224,598. The use of rolling seals are also quite common in the prior art as illustrated in U.S. Pat. Nos. 2,757,542, 2,861,456, 2,949,787 and 3,244,013.
Problems exist with prior art structures of the types noted above. For example, there is no provision in such prior art of an arrangement whereby the rolling seal or membrane is protected against the intrusion of foreign material, or the steady accumulation of foreign material which eventually may be of sufficient mass to damage the membrane prematurely. Likewise, by example, none of the above cited and discussed patents provides means for avoidance of twisting or flexing of the pipe conduit members at the junction therebetween which includes the membrane seals and structural elements of the pipe joint. Continuous flexing of the pipe members at this juncture during expansion and contraction of the pipe members can produce stress sufficient to cause structural failure of the membrane seal thus rendering the pipe joint useless for the purposes intended.
The present invention overcomes the problems noted with respect to the prior art structure and is neither taught nor suggested thereby.
It is thus an object of the present invention to provide an improved, sealed expansion joint for a conduit system.
Another object of the present invention is to provide an improved expansion joint for a conduit system that remains sealed during expansion and contraction.
Still another object of the present invention is to provide an expansion joint in which a rolling diaphragm seal of same may be easily replaced.
Yet another object of the present invention is to provide an improved expansion joint for pipes and the like by providing the same with a structural arrangement which will protect a sealing membrane therefor at all times especially during extreme contraction and elongation of the pipe members to which it is associated.
Still further, another object of the present invention is to provide a constantly sealed expansion joint which avoids twisting, flexing or angular movement between the connecting pipe members to which the expansion joint is connected.
Another object of the present invention is to provide an improved expansion joint for conduit which includes a sealing membrane.
Generally speaking, the sealed expansion joint for connecting two conduit sections according to the present invention comprises a first member connectable to one of said conduit sections, said first member having a flange located therearound with a plurality of openings defined therein; a second member connectable to the other of said conduit sections, said first and second members being telescopeable with respect to each other, said second member having a flange therearound with a plurality of openings defined therein aligned axially with openings in said flange on said first member; a rolling seal removably secured at opposite ends to said members to effect a seal therebetween; means located about a portion of said seal to guide rolling of said seal and to shield said seal from external environs; and a plurality of guide rods removably secured between said flanges and being moveable with respect to one of said flanges whereby during expansion and contraction said seal is rolled while avoiding twisting stresses.
More particularly, the joint members are cylindrical in shape with one of the members having a free end that is smaller in diameter than the other to telescope within the other. The smaller diameter member defines a shoulder adjacent the outer free end with a threaded end section. An annular cap is threadably received about said threaded end section and locks an end of said seal against said shoulder. An opposite end of said seal is secured between said flange on said other of said joint members and a portion of an annular shield that extends downwardly therefrom and surrounds a portion of the seal intermediate its length. An inside surface of the downwardly extending portion of the annular member guides the rolling of the seal while protecting the seal from the elements.
More particularly, the present invention preferably includes an annular member surrounding the rolling membrane seal connected between the telescoping cooperative members of the joint members which guide the rolling action. The annular member is preferably in the form of an inwardly turned shoulder which surrounds the inner telescoping member with sufficient clearance to prevent contact therewith during use. The inner turned shoulder prevents the ingress of foreign material from coming in contact with the membrane seal and thereby completely lessens or eliminates the buildup of foreign material in the space adjacent the seal thereby preventing damage thereto as the seal is rolled during expansion and contraction of the pipe members.
In order to prevent twisting and angular displacement of the joint members, the expansion joint is preferably provided with a plurality of connecting rods arranged to surround the ends of the joint members, being secured to the respective flanges. These rods serve as guides for the movement of structural elements of the pipe joint and to prevent twisting therebetween and angular displacement of the pipe members. The rods are positioned outwardly from the axis of the pipe members a distance sufficient to enhance the prevention of these adverse actions.
Connecting rods as employed not only guide the joint members during expansion and contraction movement, but also permit ready replacement of the rolling seal. With a portion of the annular shield for the seal mating with the flange on the first joint member, an outer end of the seal can be secured therebetween, and with the mating portion of the shield and the end of the seal having openings that match openings in the flange, the guide rods can pass therethrough with locking members on the guide rods securing the end of the seal therebetween. Once it is desirable to remove or replace the seal, the rods may be removed, thus releasing the annular shield which may be moved away, releasing the end of the seal and exposing the rolling portion. The annular end cap on the inner member may then be removed releasing the other end of the seal.
These and other objects of the present invention will become obvious after reading the following description taken in conjunction with the drawings wherein: